74AC139SC Equivalent & Substitute Parts

Part Overview

The 74AC139SC is a Decoder/Demultiplexer logic IC featuring a 1 x 2:4 circuit configuration in a 16-SOIC surface mount package. Manufactured by onsemi, this component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design requirements and procurement needs. The 74AC139 series decoder/demultiplexer is widely used in digital logic applications requiring address decoding and signal demultiplexing functions.

Substiute Parts

74AC139SC

onsemiIn Stock: 100974AC139SC Datasheet

Current PartRFQ

MC74AC139DR2G

onsemiIn Stock: 3782MC74AC139DR2G Datasheet

DirectRFQ

74AC139SCX

Fairchild SemiconductorIn Stock: 3511574AC139SCX Datasheet

SimilarRFQ

MC74AC139DG

onsemiIn Stock: 1611MC74AC139DG Datasheet

Parametric EquivalentRFQ

CD74AC139M

Harris CorporationIn Stock: 3704CD74AC139M Datasheet

SimilarRFQ

CD74AC139M96

Harris CorporationIn Stock: 2125CD74AC139M96 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74AC139SC is determined by strict equivalence across the following critical parameters:

• Circuit configuration (1 x 2:4 decoder/demultiplexer)
• Independent circuits count (2)
• Output current specifications (24mA high, 24mA low)
• Voltage supply range (2V ~ 6V minimum)
• Operating temperature range (-40°C ~ 85°C minimum)
• Package type (16-SOIC surface mount)
• Base product number (74AC139)

Substitute parts are grouped into three categories based on their relationship to the main part:

Direct Manufacturer Substitutes: Parts from the same manufacturer (onsemi) with identical electrical specifications and active product status.

Similar Manufacturer Substitutes: Parts from alternative manufacturers (Fairchild Semiconductor, Harris Corporation) with matching circuit configuration and electrical parameters but potentially different compliance or temperature ratings.

Parametric Equivalents: Parts meeting all critical electrical and mechanical parameters with active product status.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: MC74AC139DR2G (onsemi) is the preferred direct substitute. This part maintains identical electrical specifications, voltage supply range, and operating temperature range as the 74AC139SC. It carries active product status and ROHS3 compliance, ensuring long-term availability and regulatory alignment. The Tape & Reel packaging format supports automated assembly processes.

Secondary Recommendation: 74AC139SCX (Fairchild Semiconductor) provides functional equivalence with active product status. This part meets all critical electrical and mechanical parameters and offers high inventory availability (35,026 pcs). Selection of this part should account for any design-specific requirements regarding manufacturer qualification.

Tertiary Recommendation: MC74AC139DG (onsemi) serves as a parametric equivalent with active product status and ROHS3 compliance. The Tube packaging format is suitable for manual assembly or lower-volume applications. This part maintains identical specifications to the primary recommendation with alternative packaging.

Legacy Alternatives: CD74AC139M and CD74AC139M96 (Harris Corporation) are functionally equivalent but carry obsolete product status and RoHS non-compliance. These parts should be considered only when new product alternatives are unavailable and legacy system maintenance is required.

Frequently Asked Questions (FAQ)

Q: Can MC74AC139DR2G directly replace 74AC139SC in existing designs?

A: Yes. MC74AC139DR2G maintains identical electrical specifications, voltage supply range (2V ~ 6V), output current ratings (24mA), operating temperature range (-40°C ~ 85°C), and 16-SOIC package configuration. The primary difference is product status (active vs. obsolete) and packaging format (Tape & Reel vs. standard).

Q: What is the difference between the substitute parts listed?

A: Substitute parts differ in manufacturer, product status, and packaging format. MC74AC139DR2G and MC74AC139DG are onsemi products with active status and ROHS3 compliance. 74AC139SCX is a Fairchild Semiconductor equivalent with active status. CD74AC139M and CD74AC139M96 are obsolete Harris Corporation parts with RoHS non-compliance. All maintain identical circuit configuration and electrical performance.

Q: Are there voltage supply differences between substitutes?

A: CD74AC139M and CD74AC139M96 specify a wider voltage supply range (1.5V ~ 5.5V) compared to the 74AC139SC and onsemi/Fairchild alternatives (2V ~ 6V). This difference does not affect substitution in applications operating within the 2V ~ 6V range.

Q: Does packaging format affect electrical performance?

A: No. Packaging format (Tape & Reel, Tube, Bulk) affects handling, storage, and assembly processes but does not alter electrical specifications or functional performance. Selection should align with manufacturing process requirements.

Q: Which substitute offers the best long-term availability?

A: MC74AC139DR2G (onsemi) is recommended for long-term availability due to active product status, ROHS3 compliance, and established supply chain presence. 74AC139SCX (Fairchild Semiconductor) also provides active status with substantial inventory levels.

Q: Are there compliance considerations when selecting a substitute?

A: Yes. MC74AC139DR2G, MC74AC139DG, and 74AC139SCX carry ROHS3 compliance, suitable for applications subject to RoHS regulations. CD74AC139M and CD74AC139M96 are RoHS non-compliant and should be avoided in regulated applications.